Ultrasonic measurement method and device for multiple physical property parameters of polymer fluid

Abstract

The invention discloses an ultrasonic measurement method and device for multiple physical property parameters of a polymer fluid. According to the ultrasonic measurement method, ultrasonic waves are transmitted to the polymer fluid in the transparent container from the transducer through the wave guide rod, and a plurality of physical parameters of the fluid, including sound velocity, sound attenuation coefficient, sound reflection coefficient, density, viscosity and modulus, are dynamically and accurately measured and monitored in real time. The device comprises an ultrasonic transducer, a wave guide rod, a fluid container and a temperature control cavity, and is characterized by further comprising an ultrasonic transmitting device, a fluid injection pump, an air compressor, a waste liquid collector, a fixing device and a water bath temperature control device, the wave guide rod and one side of the fluid container are vertically distributed and connected with the fixing device, the continuous injection pump is connected with the fluid container, fluid samples can be added and cleaned, and air flow generated by the air compressor is used for drying a pipeline.

Description

Technical Field

[0001] This invention relates to polymer fluid property parameter measurement technology, specifically a multi-property parameter ultrasonic measurement method and device. Background Technology

[0002] Fluid properties typically include density, viscosity, and modulus. Accurate measurement of these parameters is crucial for material synthesis and property monitoring. Polymer fluids, in particular, exhibit rich rheological properties and complex parameter variations. Real-time monitoring of fluid properties during flow is closely related to product quality. In recent years, the application of ultrasonic measurement of fluid properties has increased significantly. For example, Chinese patent CN202223341928.5 reports an ultrasonic transducer for fluid density measurement. This invention effectively reduces sound wave propagation, solving the problem of poor sound insulation due to a single sound-absorbing layer in existing technologies, and achieving fluid density measurement. Another example is Chinese patent CN202111184685.6, which reports an online synchronous detection system and method for fluid density and flow velocity. This invention can simultaneously detect fluid flow velocity and density in real time. US patent US2024377234(A1) proposes an ultrasonic measurement device and method for fluid flow velocity and flow rate.

[0003] Given the application of ultrasonic measurement in fluid measurement, there is still a lack of effective measurement methods and devices for multiple fluid properties, especially for real-time monitoring of polymer fluid properties. There is an urgent need for a measurement device and method for multiple fluid properties. Most existing ultrasonic measurement methods use a single probe and waveguide to determine the reflection coefficient and attenuation coefficient by reflecting the echo. The main problems are as follows: (1) Directly calculating the signal based on the time domain spectrum of the echo leads to a large error between the measured value and the actual value; (2) The measurement scenario is offline measurement rather than real-time monitoring, which is difficult to apply to measurement scenarios under continuous flow; (3) The measurement results are singular, mostly single-parameter measurements, and cannot achieve simultaneous measurement of multiple fluid properties. Ultrasonic waves are mechanical waves that rely on a medium for propagation. Due to the limitation of shear wave penetration distance, they can usually only propagate longitudinal waves in fluids. When ultrasonic waves are emitted from the probe, they pass through the waveguide to reach the polymer fluid, and then are reflected at the fluid container wall. During the entire propagation process, there are multiple reflection, transmission and diffraction behaviors. Accurately describing the ultrasonic propagation process behavior through mathematical models is the key to ensuring high-precision ultrasonic measurement results.

[0004] The above analysis shows that existing ultrasonic measurement methods and devices cannot accurately and in real-time measure the physical properties of polymer fluids, mainly including acoustic parameters (sound reflection coefficient and sound attenuation coefficient) and physical properties (density, viscosity, modulus). Within the scope of existing technology searches, no literature has been reported on ultrasonic measurement methods and devices for multiple physical properties of polymer fluids. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide an ultrasonic measurement device and method for multiple physical parameters of polymeric fluids. This device and method can achieve online and offline measurement of the density, viscosity, and modulus of polymeric fluids, with higher measurement accuracy. The device features a simple structure, wide measurement range, high measurement accuracy, strong applicability, and easy operation, and can be widely used in the measurement and online monitoring of basic fluid properties in the materials and chemical industries.

[0006] The technical solution of this invention to solve the aforementioned method problem is to design an ultrasonic measurement method for multiple physical parameters of polymer fluids. This method involves directly contacting an ultrasonic sensor with the polymer fluid sample via a waveguide rod, and dynamically and accurately measuring and monitoring the sound velocity, sound attenuation coefficient, sound reflection coefficient, density, viscosity, and modulus of the polymer fluid through coordinated control of the fluid injection pump and valves. The ultrasonic frequency range is 1-25 MHz, and the frequency can be adjusted by changing the probe. This method uses air to purge and dry the container and pipes, and uses the air as a reference signal.

[0007] The technical solution of this invention to solve the aforementioned device problem is to design an ultrasonic measurement device for multiple physical parameters of polymer fluids. This device includes a fixing device, a fluid container, a waveguide rod, an ultrasonic probe, an ultrasonic generator, and a computer. Its distinguishing feature is that it also includes a fluid injection pump, an air compressor, pipeline valves, and a fluid collection device. The fluid container is fixed by the fixing device and directly connected to the waveguide rod on one side. The fluid injection pump is connected to the fluid container via a fluid pipeline. The fluid collection device is connected downstream of the fluid container via a pipeline. The fluid container's temperature is controlled by a circulating water bath. The two ends of the waveguide rod are in contact with the fluid being measured and the ultrasonic probe, respectively. The probe is connected to the ultrasonic generator via a wire to generate ultrasonic waves. The ultrasonic generator is connected to the computer to record and process the measured waveforms.

[0008] Compared with the prior art, the measuring device and method of the present invention can simultaneously measure more fluid properties while satisfying the measurement of a single physical parameter. It can not only satisfy the physical property measurement of static fluids, but also the real-time monitoring of flowing fluids. By mathematically modeling the ultrasonic propagation process, the error of the measurement results can be reduced. It has the following technical effects: (1) The present invention realizes the ultrasonic measurement of multiple physical parameters of polymer fluids, avoiding the limitation of traditional ultrasonic measurement that only has single parameter measurement results; (2) The present invention realizes the real-time monitoring of fluid physical parameters in static and flowing states; (3) When measuring in static and flowing states, by mathematically modeling the ultrasonic propagation process, the present invention not only improves the accuracy of fluid physical parameter measurement results, but also enables the measurement results to reflect the real change law of fluid characteristics. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the composition structure of one specific embodiment of the ultrasonic measurement device for multiple physical parameters of polymer fluids according to the present invention.

[0010] Figure 2 This is a schematic diagram of the installation of the waveguide rod and the polymer fluid cavity. The axis of the waveguide rod is perpendicular to one side of the sample box. One end of the waveguide rod is connected to the ultrasonic probe, and the other end is in direct contact with the polymer fluid in the sample box. The sample box wall and the waveguide rod are connected by threads. The water bath cavity wall and the waveguide rod are sealed with a rubber stopper to prevent leakage of circulating water.

[0011] Figure 3 This is a schematic diagram of ultrasound echo, where Figure 3 (a) is the reference signal. Figure 3 (b) is the sample signal. The corresponding waveform ① is the first echo, waveform ② is the second echo at the waveguide-solution interface, and waveform ③ is the third echo reflected on the left side wall of the container after passing through the sample. Detailed Implementation

[0012] The present invention will be further described below with reference to embodiments and accompanying drawings.

[0013] This invention relates to an ultrasonic measurement device for multiple physical properties of polymer fluids (hereinafter referred to as the measurement device, see [link]). Figures 1-2The present invention discloses a method for measuring multiple physical parameters of polymer fluids. The measuring device comprises a fixing device 9, a fluid container 5, a waveguide rod 4, an ultrasonic probe 3, an ultrasonic generator 2, and a computer 1. It further comprises a fluid injection pump 6, an air compressor 7, a pipeline valve 8, and a fluid collection device 10. The fluid container 5 is fixed by the fixing device 9 and directly connected to the waveguide rod 4 on one side. The fluid injection pump 6 is connected to the fluid container 5 via a fluid pipeline. The fluid collection device 10 is connected downstream of the fluid container 5 via a pipeline 14. The fluid container 5 uses a circulating water bath to control the measurement temperature. The two ends of the waveguide rod 4 are in contact with the fluid being measured and the ultrasonic probe 3, respectively. The ultrasonic probe 3 is connected to the ultrasonic generator 2 via a wire 13 to generate ultrasonic waves. The ultrasonic generator 2 is connected to the computer 1 to record and process the measured waveforms.

[0014] The waveguide rod 4 described in the measuring device of this invention (see...) Figure 2 The waveguide is composed of a quartz glass rod 4, epoxy resin adhesive 15, and a stainless steel sleeve 16. The epoxy resin adhesive 15 both fixes the quartz glass rod 4 and the stainless steel sleeve 16, bridging the gap between them, and reduces boundary noise reflection during the propagation of ultrasound waves through the quartz glass rod 4. One end of the waveguide is adjacent to the ultrasonic probe, and the diameter of the quartz glass rod 4 in the waveguide is larger than the diameter of the ultrasonic probe 3. The probe is connected to one end of the waveguide via a coupling agent 17. The other end of the waveguide is threaded to a fluid container 5, and this end face is in contact with the test sample. The container wall and the waveguide 4 are sealed with a rubber stopper to prevent leakage of the water bath liquid.

[0015] The measurement method corresponding to the measuring device of this invention is based on the following principle: the ultrasonic wave excited by the ultrasonic probe 3 propagates to the fluid being measured through the waveguide rod 4. When there is no liquid in the fluid container 5, the ultrasonic wave undergoes total reflection directly at the waveguide rod-air interface. At this time, the corresponding waveform includes two echoes ① and ② (see...). Figure 3 (a) The first echo ① is formed near the end face of the waveguide rod 4 of the ultrasonic probe 3, while the second echo ② is formed at the waveguide rod-air interface. The second echo ② serves as a reference signal for analyzing the physical properties of the sample. When the fluid container 5 contains the liquid being tested, the measured signal diagram is shown below. Figure 3 As shown in (b), the ultrasonic signal propagates through waveguide 4 into the fluid being measured, and then is reflected by the sample container wall to generate a third echo ③. This echo carries the sample information of the fluid being measured. Since the fluid measurement depth is known, the fluid sound velocity can be determined based on the flight time of the two echoes ② and ③. cThe acoustic attenuation coefficient of the fluid being measured can be determined based on the amplitude values ​​of the two echoes. α Based on the reflection system at the interface of the reference signal and the sample signal. R The number can be used to calculate the density of the fluid being measured. ρ By performing a Fourier transform on the echo signal, the sound attenuation coefficient and sound velocity at different frequencies can be calculated, thereby deriving the viscosity and modulus of the fluid being measured, and ultimately achieving the simultaneous measurement of multiple physical parameters of the fluid being measured.

[0016] The measuring device of this invention has the following functions: (1) The depth of the sample can be measured by rotating the waveguide rod close to the thread on the side of the sample box of the fluid being measured. (2) The ultrasonic measurement frequency can be changed by changing the ultrasonic probe. (3) Different temperature measurement conditions and fluid property parameters under varying temperature conditions can be set by controlling the water bath temperature controller. (4) Real-time measurement of static and dynamic fluid states can be achieved by controlling the closing of the upstream and downstream pipeline valves. (5) Fluid property parameters can be measured under different pressures by turning on the upstream fluid injection pump and closing the downstream valve.

[0017] Any aspects not covered in this invention are applicable to existing technologies.

[0018] Specific embodiments of the present invention are given below. These embodiments are only used to further illustrate the present invention, but do not limit the scope of protection of the claims of the present invention.

[0019] Example 1

[0020] This embodiment uses the measuring device described in this invention (such as...). Figure 1 As shown in the figure, the physical properties of an aqueous solution of polyethylene oxide (PEO) (a shear-thinning fluid) were measured. The parameters are as follows: The excitation voltage of the ultrasonic generator 2 is 300 V, and the ultrasonic probe 3 used is a broadband probe with a center frequency of 5 MHz and an effective bandwidth range of 2.5 ~ 7.5 MHz. The test temperature of the PEO aqueous solution is set to 25 ℃ at room temperature. The temperature of the test solution is controlled within the target temperature range by the water bath temperature controller 11 to achieve constant temperature measurement at 25 ℃. The molecular weight of the PEO used in the experiment is 1 million. The specific measurement method is as follows: (1) Preparation before the test: Empty the container 5 containing the fluid to be tested, open the pipeline valve 8, and clean the pipeline 12 and sample container 5 by injecting deionized water into the continuous injection pump 6. Then, inject anhydrous ethanol into the continuous injection pump 6 to deeply clean the pipeline and sample box. Next, turn off the continuous injection pump 6, turn on the air compressor 7, and introduce air into the pipeline and fluid container until there is no residual deionized water and anhydrous ethanol in the entire pipeline and sample box. (2) Turn off the air compressor 7, turn on the ultrasonic generator device 2 switch and the computer 1, and collect the reference signal. (3) Turn on the continuous injection pump 6 and transport the sample to be tested through the pipe 12 to the fluid holding container 5. When the sample flows into the downstream sample collection container 10, close the pipe valves 8 at both ends of the upstream and downstream pipes at the same time, so that the sample to be tested in the sample holding container 5 remains in a static and stable state. (4) Adjust the water bath controller 11, set the corresponding measurement temperature, wait for 30 minutes of circulating water bath time to stabilize the measurement temperature of the fluid to be tested, and then turn on the ultrasonic generator device 2 and the computer 1 to collect the sample signal. (5) By comparing the reference signal and the sample signal, the ultrasonic emission coefficient of the waveguide interface can be calculated, and then the density of the PEO aqueous solution can be calculated according to the relationship between acoustic impedance, density and sound velocity. Repeat the above 5 steps to measure the density, viscosity and modulus changes of different mass concentrations and molecular weights. The measurement results show that the density, viscosity and modulus obtained by ultrasonic measurement are basically consistent with the physical property parameters of pure water at room temperature of 25 ℃, and the measurement accuracy of the three physical property parameters is greater than 97%. Meanwhile, the density, viscosity, and modulus of PEO aqueous solution are directly proportional to the mass concentration and molecular weight of PEO.

[0021] This embodiment demonstrates that the ultrasonic measuring device and method of the present invention can realize real-time measurement of the physical properties of polymer fluids under dynamic and static conditions, including the sound velocity, sound attenuation coefficient, density, viscosity and modulus of the fluid.

[0022] Example 2

[0023] To verify the accuracy of this invention in Newtonian fluids, offline measurements were performed using glycerol / water solutions of different ratios. This embodiment employs the measuring device described in this invention (such as...). Figure 1As shown), the physical properties of an aqueous glycerol solution (a Newtonian fluid) were measured offline. The test procedure included: (1) Preparation: Clean the pipeline and collect the air reference signal according to Example 1; (2) Sample injection: Inject the aqueous glycerol solution and close the upstream and downstream valves 8 to allow the sample to stand; (3) Temperature control: Set the temperature range of 20–40℃ and measure once every 5℃; (4) Ultrasonic acquisition: Use a broadband probe with a center frequency of 10 MHz to acquire the echo sequence. The measurement results obtained in this example showed that: the sound velocity of the aqueous glycerol solution decreased monotonically with increasing temperature; the attenuation coefficient increased significantly with increasing glycerol concentration; the calculated density was more than 98% consistent with the literature data; and the viscosity calculation results deviated less than 5% from the rotational viscometer.

[0024] This embodiment demonstrates that the measurement method of the present invention can obtain high-precision physical property parameters in Newtonian fluids, and can also serve as an effective verification method for the measurement method.

[0025] Example 3

[0026] This embodiment demonstrates the ability of the present invention to monitor non-Newtonian fluids in real time under continuous flow conditions. This embodiment employs the measuring device described in the present invention (such as...). Figure 1 As shown), the physical properties of corn starch aqueous solution (shear-thickening fluid) were measured. Corn starch aqueous solution is a typical shear-thickening fluid, and the viscosity increases rapidly in the high shear region. The measurement process of this embodiment includes: (1) setting up the flow scenario: opening the upstream injection pump and the downstream collection device valve 8, and setting the flow range to 10~100 mL / min; (2) starting the flow rate change experiment: recording 30 s continuous ultrasonic signals at each flow rate, and converting the flow velocity into the shear rate parameter of the fluid according to the geometric dimension parameters; (3) starting ultrasonic acquisition and signal processing, and calculating the change trend of sound velocity, attenuation coefficient and modulus with flow velocity in real time. The measurement results obtained in this embodiment show that: in the low flow velocity (shear rate) region, the viscosity remains stable; when the flow velocity exceeds the critical value, the sound attenuation coefficient and equivalent modulus increase sharply, reflecting the enhancement of the fluid microstructure induced by shear; the online measurement method proposed in this invention can accurately capture the time point of shear thickening.

[0027] Example 4

[0028] Boger fluids exhibit near-constant viscosity but significant elasticity. This embodiment verifies the invention's ability to measure viscoelastic parameters by performing ultrasonic measurements on an aqueous solution of polyvinylpyrrolidone (PVP). This embodiment utilizes the measuring device described in this invention (such as...). Figure 1As shown in the figure, physical property parameters of PVP aqueous solutions with different mass fractions (2~10%) were measured. The specific implementation steps include: (1) measuring the sound velocity, attenuation and reflection coefficient in offline measurement mode; (2) maintaining stable fluid flow by adjusting valve 8 in online mode; and obtaining the changes in storage modulus and loss modulus based on frequency domain analysis. The measurement results obtained in this embodiment show that the sound velocity changes little with concentration, but the attenuation coefficient increases linearly with frequency; the storage modulus increases slightly with the flow shear rate, which is consistent with the weak shear sensitivity characteristics of Boger fluid. This embodiment shows that the present invention can obtain fluid elasticity and acoustic parameters simultaneously on the same platform.

[0029] The ultrasonic multi-property parameter measurement method proposed in this invention has high universality. Its core measurement is based on the echo characteristics (sound velocity, reflection coefficient, attenuation coefficient) in the acoustic overtone process and the general relationship between acoustic impedance and material viscoelasticity. Therefore, it can be applied to a variety of systems, including but not limited to: (1) Newtonian fluids: such as alcohols, sugar solutions, salt solutions, homogeneous monomer solutions, etc. (2) Shear-thinning fluids: including polymer solutions such as PEO, PAM, CMC, hyaluronic acid, alginate, etc. (3) Shear-thickening fluids: nanoparticle suspensions, starch, clay systems, etc. (4) Viscoelastic fluids and Boger fluids: such as PVP, PI, PAAm, silicone oil polymer mixtures, etc. (5) Industrial slurries: ceramic slurries, catalyst slurries, battery electrode slurries, coatings, etc. (6) Biological and food systems: protein solutions, emulsions, colloidal food matrices, etc. (7) Industrial reaction systems: polymerization reaction intermediate liquids, enzyme catalytic suspensions, fermentation broths and process monitoring fluids, etc.

[0030] In summary, the method of the present invention is not only applicable to the above embodiments, but can also be extended to more types of complex fluid systems according to the application scenario, so as to achieve high-precision, multi-parameter, dynamic real-time monitoring.

Claims

1. An ultrasonic measurement method for multiple physical parameters of polymer fluids, wherein the ultrasonic sensor is in direct contact with the polymer fluid sample via a waveguide rod, and the fluid injection pump and valve are controlled in a coordinated manner to dynamically and accurately measure and monitor the sound velocity, sound attenuation coefficient, sound reflection coefficient, density, viscosity and modulus of the polymer fluid; the ultrasonic sensor corresponds to an ultrasonic frequency range of 1-25 MHz, and the frequency of the ultrasonic wave can be adjusted by changing the probe.

2. The ultrasonic measurement method for multiple physical parameters of polymer fluids according to claim 1, characterized in that... This method empties and dries containers and pipes with air, using air as a reference signal.

3. An ultrasonic measurement device for multiple physical properties of polymer fluids as described in claim 1 or 2, the device comprising a fixing device, a fluid holding container, a waveguide rod, an ultrasonic probe, an ultrasonic generator, and a computer, characterized in that... It also includes a fluid injection pump, an air compressor, pipeline valves, and a fluid collection device. The fluid container is fixed by a fixing device and directly connected to a waveguide rod on one side. The fluid injection pump is connected to the fluid container through a fluid pipeline. The fluid collection device is connected downstream of the fluid container through a pipeline. The fluid container's temperature is controlled by a circulating water bath. The two ends of the waveguide rod are in contact with the fluid being measured and the ultrasonic probe, respectively. The probe is connected to an ultrasonic generator through a wire to generate ultrasonic waves. The ultrasonic generator is connected to a computer to record and process the measured waveforms.

4. The ultrasonic measuring device for multiple physical parameters of polymer fluids according to claim 3, characterized in that... The waveguide rod is directly connected to the ultrasonic probe via a coupling agent, and the diameter of the waveguide rod is larger than the diameter of the probe.

5. The ultrasonic measuring device for multiple physical parameters of polymer fluids according to claim 3, characterized in that... Ultrasonic measurements of polymer fluids under dynamic and static flow conditions are achieved by adjusting pipeline valves.

Images